Organo-silicon compounds

ABSTRACT

New siloxyalkylene polymers prepared by reacting organochlorosilanes or alkoxysilanes with alkylene or oxyalkylene diols and which are useful as surface active agents particularly for suppression of foam formation in aqueous systems e.g., in fermentation processes.

O United States Patent 1 91 1111 3,865,859

Plumb Feb. 11, 1975 ORGANO-SILICON COMPOUNDS 3,194.773 7/1965HOSieIllCl' 260/4486 R x 3,272,762 9/1966 lbbotson et ul, 260/4488 R X[751 Inventor Bake Plumb Mancheste 3.480.583 11/1969 Bailey et 21].260/448.8 R x England $555,063 1/1971 Nakajima 6161 260/4486 R 3.6004188/197! Bailey et al. 260/448.8 R [73] Assgnee' {ma /3' f g g f g'3,629,310 12/1971 Bailey et ill. 260/4488 R I 3,686,254 8/1972 Morehouse260/4482 B [22] Fil d; A 24, 1972 3 723,49l 3/l973 Rossmy et al.260/4482 B [2]] Appl' 283288 Primary Examiner-Daniel E. Wyman AssistantExaminerPaul F. Shaver [30] Foreign Application Priority Data Attorney,Agent, or FirmCushman, Darby &

Aug. 3l, l97l Great Britain 40534/7l Cushman [52] US. Cl..... 260/448.8R, 252/358, 260/448.2 B [57] ABSTRACT [5i] llnt. Cl. C07f 7/18 New Siloxyalkylene polymers prepared by reacting or- [58l F' 4 Aganochloro-silanes or alkoxysilanes with alkylene or 6 oxyalkylene diolsand which are useful as surface ac- [5 1 References tive agentsparticularly for suppression of foam forma- UNITED STATES PATENTS tionin aqueous systems e.g., in. fermentation pro- 2,834.748 5/1958 Baileyet a], 260/4488 R X cesses. 3,170,894 2/1965 Brown et al..... 260/4488 RX 3,172,899 3/1965 Bailey 260 4482 B 8 Drawmgs ORGANO-SILICON COMPOUNDSThis invention relates to new and useful organosilicon compounds and tothe use of such compounds for the suppression of foam formation.

A wide variety of organosilicon compounds is known and many of theseincluding large numbers of siloxane/oxyalkylene copolymers have beenused for the suppression of foam in various media. Many of thesecompounds are not entirely satisfactory, however, especially when usedfor the suppression of foam formation in aqueous systems such as areused in various fermentation processes.

According to the present invention a new and useful class oforganosilicon compounds comprises compounds of the general formula whereR is a substituted or unsubstituted monovalent hydrocarbyl group, A isthe group [(C,,H ,,O),,. C,,H or C l-i where n is an integer from 2 to 4and y is an integer from 1 to 5, a is or 1, x is an integer from 1 to100 and z is an integer which when a is l is not greater than x 2 andwhen a is O is not greater than 2x 2.

The substituted or unsubstituted monovalent hydrocarbyl group R may bean alkyl, aryl, aralkyl, alkaryl, alkenyl, cycloalkyl or cycloalkenylgroup, preferably containing not more than 10 carbon atoms, or such agroup containing substituents selected from halogens and cyano groups.Suitable groups include, for example, methyl, ethyl, propyl, isohutyl,vinyl, phenyl, tolyl and benzyl groups. in many cases it is preferredthat the groups R are methyl or phenyl groups.

A wide variety of groups A may be present. These inelude, for example,

While a may be 0 or I, it is in many cases preferred that it be 1.

.r may as stated vary from 1 to 100. It is, however, in generalpreferred that it be from 1 to 10 while for some purposes it isespecially preferred that x be 1.

While y may be from 1 to 5 it is preferred in many cases that it be 1 or2.

The values of 1 may vary widely it being necessary only that when a is lit be not greater than x 2 and that when a is 0 it be not greater than2.\' 2. It is, however, frequently preferred that it be not less than.r.

The products of the invention may be prepared by any one of a number ofmethods. One convenient method is to react silicon tetrachloride or anorganotrichlorosilane of the formula RSiCLg with a suitable dihydroxycompound. Suitable compounds are the diols corresponding to the groupsA, for example, HOCH- CH(CH )OH, HOCH(CH )CH OCH CH(CH- ;,)OH, HOCl-l CHOCH CH OH, HOCH CH OH, HO(CH CH O) H, HO(CH OH, HO[CH(CH )C- H O],,H andHOC(CH C(CH OH. The reaction is preferably carried out by adding thechlorosilane to the dihydroxy compound which is preferably dissolved inan inert solvent. Suitable solvents which may be used include, forexample, toluene, benzene, xylene, diethyl ether and dibutyl ether. Ifdesired, the reaction may be carried out in the presence of an acidacceptor to combine with the hydrogen chloride evolved during thereaction. Suitable acid acceptors include, for example, organic basessuch as pyridine, N,N-diethylaniline, triethylamine and tri-n-butylamineand ammonia. Acid acceptors are, however, not always necessary and inmany cases complete removal of the hydrogen chloride can conveniently beachieved by purging the reaction mixture with a stream of an inert gassuch as nitrogen. When an acid acceptor is employed, it is preferred tocarry out the process in the presence of a solvent. Heat is evolved andcooling of the reaction mixture is desirable during the process ofaddition of the chlorosilane to the dihydroxy compound in order tomaintain the temperature of the reaction mixture below about 4050C. Thereaction mixture is then heated, usually to its reflux temperature, tocomplete the reaction, after which the precipitated amine hydrochlorideis filtered off and the product recovered by removal of the solvent bydistillation.

When no acid acception is employed, the silicon tetrachloride or theorganotrichlorosilane is added to the solution of the dihydroxycompound, again maintaining the temperature of the reaction mixturebelow about 4050C during the addition. Thereafter the solution is heatedgradually to reflux temperature and purged with a stream of a dry inertgas, such as nitrogen. until acid-free. The product is then recovered bydistillation of the solvent.

In another method a tetraalkoxysilane or organotrialkoxysilane isreacted with a. suitable dihydroxy compound in a transesterificationreaction. Preferably the alkoxysilane is so chosen that the free alcoholproduced is of lower boiling point than the dihydroxy compound used. Thereactants are heated together, if desired in the presence of a solventand the free alcohol produced removed by distillation, if necessaryunder reduced pressure. If desired an acidic catalyst, such as, forexample, trifluoroacetic acid or monochloroacetic acid alone or inpresence of an alkali metal salt thereof, for example, trifluoroaceticacid with potassium trifluoroacetate or potassium acetate or a basiccatalyst such as potassium hydroxide or a potassium silanolate, KO[Si(CHO] K (where b is a positive integer), may be employed in thetrans-esterification reaction. The alkoxysilanes used are preferably ofthe type Si(OR), or RSi(OR) where R is a lower alkyl group such asmethyl, ethyl, iropropyl or n-butyl group. When such alkoxysilanes areemployed, removal of the evolved alcohol R'-OH by distillation, ifnecessary azeotropic with a suitable solvent such as toluene or xyleneoccurs readily, and in such cases a catalyst for the transesterificationreaction is not usually necessary.

The ratio solvent to reactants employed in either of the above processesis not critical, equal parts by weightof solvent and reactants beingsatisfactory in most cases, but more or less may be employed if desired.When removal of alcohol by azeotropic distillation with the solvent iscarried out in the transesterification process, fresh solvent may beadded as the azeotrope is removed to maintain an approximately constantsolution concentration.

The molar ratio of dihydroxy compound to chlorosilane or alkoxysilaneemployed in these processes may vary widely. 1f the molar ratio ofdihydroxy compound to silicon compound is 3:1 or greater, in the use oftrichlorosilanes or trialkoxysilanes, the product will consist almostexclusively of a compound of the structure RSi[(OC,,H ,,),,OH] or C H Asthe molar ratio of dihydroxy compound to silicon compound employed isdecreased to a value of slightly greater than 1.5:], the average numberof cross links per silicon atom will increase, and the average number of-O-R-OH groups (where R is the group -(C,,H ,,O),,.,C,,H or C H attachedto any silicon atom in the product will decrease. When the limitingmolar ratio of reagents of .1.5:1 is reached, the resultant product willcontain no -O-R"OH groups attached to silicon, but will consistsubstantially of a mixture of molecular species of average compositionnumber of cross-links per silicon atom will again increase until, whenthe limiting molar ratio of reagents of 2:1 is reached, the resultantproduct will contain no O-R-Ol-l groups attached to silicon but willconsist entirely of a mixture of molecular species of averagecomposition [Si(O.-R"-O) where d is a positive integer.

Our invention is further illustrated by the following examples in whichall parts and percentages are by weight except where otherwise stated.

EXAMPLE 1.

A solution of 603 parts of di-(2-hydroxy-n-propyl) ether in 750 parts oftoluene was heated under reflux, dried by azeotropic distillation andcooled to 12C.

' 149.5 parts of methyltrichlorosilane were added to the solution withvigorous stirring over a period of 20 minutes the temperature of thereaction mixture during addition being maintained in the range l220C bycooling. The mixture was then stirred at 20-25C for 1 hour after whichit was heated to reflux temperature over a period of 30 minutes with abrisk stream of nitrogen passing continuously through the mixture.Heating under reflux and purging of the mixture with nitrogen wascontinued for 3 hours after which time the offgases were acid free.Toluene was then removed by distillation at a temperature of 100C and 10mm. Hg pressure to leave 635 parts ofa clear colourless mobile 011. Themolar ratio of di-( 2-hydroxy-n-propyl) ether to methyltrichlorosilaneemployed was 4.5: 1 The product contained no detectable free acidity(i.e. 5 ppm. as HC1) as determined by heating a sample under reflux withwater/acetone (/20) for 20 minutes and titrating to bromothymol bluewith N/ aqueous sodium hydroxide solution.

The antifoam properties of the products were tested as follows:

50 ml of a 0.25 percent aqueous solution of a secondary alkylsulphatesurfactant (Teepol X) was placed in a 100 ml beaker of base diameter 50mm. A line stream of air bubbles was blown through the solution by meansof a 20 mm diameter No. 3 sintered glass bubbler placed at the bottom ofthe solution. The air flow rate was such that the foam formed took oneminute to reach the top of the beaker (i.e. a foam height of 30 mm). Anair flow rate of about 60 ml per minute was required to produce thiseffect. When the top of the foam was level with the top of the beaker0.1 ml of the material under test was spread from a 1 ml pipette on tothe surface of the foam. The foam subsided immediately and took 2minutes to reconstitute (i.e. reach the top of the beaker again).

In addition to the test described above the product was examined in abiochemical fermentation process as follows:

A solution was prepared containing 35 g of sugar in 140 g of water. Tothis solution were added 25 g of concentrated fruit juice (pineapple andpeach juices) and 0.5 g of bakers yeast. The mixture was stirred well ina 500 ml covered flask and allowed to ferment whilst maintained at atemperature of 24-27C. After 17 hours, steady evolution of carbondioxide was occurring and a white foam covered the entire surface of theliquid. After 31 hours, the foam was still present over the entiresurface, and a total of l 100 ml of carbon dioxide had been evolved.

A similar mixture treated at the start with 0.2 g of the productprepared as described above evolved carbon dioxide, but produced no foamon the surface of the liquid. After 17 hours, the surface of the liquidwas completely free of foam, and remained so after 31 hours, by whichtime a total of 1430 ml of carbon dioxide had been evolved.

A laboratory scale batch culture of a methanol oxidisable organism toproduce single cell protein was carried out. The use of 0.1 per cent byvolume of the product prepared as described above controlled surfacefoam without adversely affecting the bubble size and air distribution inthe mass. There was also no toxic effect on the culture and no decreasein the yield of protem.

EXAMPLES 2 4.

Products were prepared by a process similar to that of Example 1 fromdi-(2-hydroxy-n-propyl) ether and methyltrichlorosilane in the molarproportions given below. Reactions were carried out at 50 percentconcentration in toluene. Details of the products obtained are alsogiven below together with the results of testing the antifoam propertiesin the manner described in Example 1.

Molar proportion di-(2- Product TlME (Seconds) Example hydroxy-n propylether: Product Viscosity Foam Foam methyltrichlorosilane Appearance cSat 25C) Subsidence Reconstitution 2 3.0:1 Clear, colourless 84 Immediate3 2.2:1 Clear. colourless 78 do. 120 4 1.5311 Clear, colourless 202 do.120

EXAMPLE 5.

The procedure of Example 1 was used to prepare a product from 114.0parts of 1.2-dihydroxypropane, CH CH(OH)CH OH, and 74.75 parts ofmethyltrichlorosilane in 189 parts of toluene. This represents a molarratio of 1,2-dihydroxypropane to methyltrichlorosilane of 3.0: 1. 70parts of product was obtained as a clear colourless oil of viscosity 526centistokes at 25C. It was found in testing in the manner described inExample 1 that the foam subsided in 20 seconds and was reconstituted in3.5 minutes.

EXAMPLE 6.

The procedure of Example 1 was used to prepare an anti-foam product from294 parts of di-(2-hydroxy-npropyl) ether and 211.5 parts ofphenyltrichlorosilane in 506 parts of toluene. This respresents a molarratio of di-(Z-hydroxy-n-propyl) ether to phenyltrichlorosilane of2.211. 74 parts of product was obtained as a clear colourless oil ofviscosity 362 centistokes at 25C. Testing in the manner described inExample 1 gave partial foam subsidence in seconds and reconstitution in1 minute.

EXAMPLE 7.

A mixture of 120.6 parts of di-(Z-hydroxy-n-propyl) ether and 35.6 partsof methyltriethoxysilane was heated for two hours to a temperature of110120C whilst purging with a brisk stream of nitrogen. This representsa molar ratio of do-(2-hydroxy-n-propyl) ether to methyltriethoxysilaneof 4.521. The off-gases were condensed in an ice/water cooled tap. Themixture was distilled for 30 minutes at a temperature of l10-l20C and apressure of 10 mm. Hg, the condensate being collected in a cooled trap.A combined total of 25.9 parts of condensate were collected which werefound to consist entirely of ethanol. The residue consisted of 1302parts of a clear, colourless liquid of viscosity 113.0 cS at 25C.Testing in the manner described in Example 1 gave immediate foamsubsidence and 5 minutes were required for reconstitution.

EXAMPLE 8.

A minute of 268 parts of di-(2-hydroxy-n-propyl) ether and 104 parts oftetraethoxysilane was heated for 5 hours to a temperature of l60-200Cwhilst purging with a slow stream of nitrogen. During that time 68.4

uct in the manner described in Example 1 gave 5 seconds for subsidenceand 3.5 minutes for reconstitution.

What we claim is: l. Organosilicon compounds of the general formulawhere R is an alkyl, aryl and alkenyl group; A is the group [(C H ,,O),,,C,,H or (C H where n is an integer from 2 to 4 and y is an integer from1 to 5; a is 0 or 1;.r is an integer from 1 to 10; and z is an integerwhich when a is l is not greater than 1' 2 and when a is 0 is notgreater than 2x 2.

2. Compounds according to claim 1 wherein the group R contains not morethan 10 carbon atoms.

3. Compounds according to claim 2 wherein the group R is selected fromthe group consisting of methyl and phenyl groups.

4. Compounds according to claim 1 wherein Z is not less than x.

5. A process for the production of compounds claimed in claim 1comprising reacting a silicon halide selected from the group consistingof silicon tetrachloride and organotrichlorosilanes of the formula RSiClwith a dihydroxy compound.

6. A process for the production of compounds claimed in claim 1comprising transesterifying an al koxysilane selected from the groupconsisting of tetraalkoxysilanes, organotrialkoxysilanes with adihydroxy compound.

7. A process according to claim 6 wherein the alkoxy groups are sochosen that the free alcohol produced is of lower boiling point than thedihydroxy compound used.

8. A process according to claim 6 wherein the alkoxysilanes selectedfrom the group consisting of alkoxysi lanes of the formula Si(OR') andRSi(OR') where R is selected from the group consisting of methyl, ethyl,isopropyl, n-butyl groups and R is selected from the group consisting ofmethyl and phenyl groups.

1. ORGANOSILICON COMPOUNDS OF THE GENERAL FORMULA
 2. Compounds accordingto claim 1 wherein the group R contains not more than 10 carbon atoms.3. Compounds according to claim 2 wherein the group R is selected fromthe group consisting of methyl and phenyl groups.
 4. Compounds accordingto claim 1 wherein z is not less than x.
 5. A process for the productionof compounds claimed in claim 1 comprising reacting a silicon halideselected from the group consisting of silicon tetrachloride andorganotrichlorosilanes of the formula RSiCl3 with a dihydroxy compound.6. A process for the production of compounds claimed in claim 1comprising transesterifying an alkoxysilane selected from the groupconsisting of tetraalkoxysilanes, organotrialkoxysilanes with adihydroxy compound.
 7. A process according to claim 6 wherein the alkoxygroups are so chosen that the free alcohol produced is of lower boilingpoint than the dihydroxy compound used.
 8. A process according to claim6 wherein the alkoxysilanes selected from the group consisting ofalkoxysilanes of the formula Si(OR'')4 and RSi(OR'')3 where R'' isselected from the group consisting of methyl, ethyl, isopropyl, n-butylgroups and R is selected from the group consisting of meThyl and phenylgroups.